pkt_sched: set root qdisc before change() in attach_default_qdiscs() (e57a784d) · Commits · 戴 / test

After commit ("pkt_sched: give visibility to mq slave qdiscs") we call disc_list_add() while the device qdisc might be the noop_qdisc one. This shows up as duplicates in "tc qdisc show", as all inactive devices point to noop_qdisc. Fix this by setting dev->qdisc to the new qdisc before calling ops->change() in attach_default_qdiscs() Add a WARN_ON_ONCE() to catch any future similar problem. Signed-off-by:

Eric Dumazet <edumazet@google.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/sched/sch_api.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -273,8 +273,11 @@ static struct Qdisc qdisc_match_from_root(struct Qdisc root, u32 handle)

		void qdisc_list_add(struct Qdisc *q)
		{
		struct Qdisc *root = qdisc_dev(q)->qdisc;

		WARN_ON_ONCE(root == &noop_qdisc);
		if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
		list_add_tail(&q->list, &qdisc_dev(q)->qdisc->list);
		list_add_tail(&q->list, &root->list);
		}
		EXPORT_SYMBOL(qdisc_list_add);

net/sched/sch_generic.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -718,8 +718,8 @@ static void attach_default_qdiscs(struct net_device *dev)
		} else {
		qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);
		if (qdisc) {
		qdisc->ops->attach(qdisc);
		dev->qdisc = qdisc;
		qdisc->ops->attach(qdisc);
		}
		}
		}

Admin message